1. Field of the Invention
The present invention relates to a thread cutting device in a sewing machine, and in particular to a thread cutting device that is selectively operable to cut both upper and lower threads or to only cut an upper thread.
2. Description of the Related Art
Japanese Laid-Open Utility Model Publication No. 2-67980 teaches a thread cutting device in a sewing machine that comprises a movable knife and a fixed knife, which cooperate with each other in order to cut a thread or threads. In order to selectively cut both upper and lower threads or only an upper thread, a lower thread evacuating lever and an actuation mechanism associated therewith are provided. When only the upper thread is to be cut, the evacuating lever is actuated at a predetermined timing during the movement or the movable knife or during the rotation of a hook so as to engage and move the lower thread out of the moving path of the movable knife.
However, due to the incorporation of the evacuating lever and its associated actuation mechanism, operation timing adjustments of the evacuating lever, as well as maintenance work on the evacuating lever and its associated actuation mechanism, are required. In addition, this design may increase the number of parts that are necessary to cut the threads.